The present invention relates generally to an automatically actuated device for removing a swaged metal collar or nut like member from a two piece lockbolt type fastener. Lockbolt type fasteners have been in use for many years. A typical example is shown in U.S. Pat. No. 4,342,529 to J. Ruhl and R. Dixon, which is incorporated herein by reference. Additional examples of such fasteners, which may also be referred to as two piece swage type fasteners include those shown in U.S. Pat. No. 3,915,053 to J. Ruhl and U.S. Pat. No. 2,531,048 to L. Huck. In each case the fastener comprises a pin and a generally annular collar adapted to be swaged into annular, non-helical lockgrooves in the pin. Because the collar is generally annular and the lockgrooves non-helical it is not possible to torque the collar off the fastener pin when one wishes to disassemble the joint secured by the fastener, as one can do with a helically threaded bolt and nut combination type fastener. Instead conventional practice has usually been to cut off the collar with a single bladed cutting chisel impacted either by a pneumatically actuated hammer or a hand held hammer. Such means are often unsatisfactory because of the time or energy required to complete the job. Further, in many instances there is not sufficient access to the fastened joint to permit such methods. An additional hardship is encountered with such techniques when the collar includes a prominent flange at the base of the fastened joint since chisel blade tends to ride over the flange. Even further, one cut through the collar rarely spread the collar sufficiently to allow the pin lockgrooves to completely disengage the interfitting swaged collar portions whereby the pin can be slipped out of engagement with the collar.
Another past practice includes cutting the collar off with a torch. Yet another technique, limited to non-flanged collars has been a hydraulically actuated collar cutter including two diametrically opposed, single edged cutting blades wherein one blade is hydraulically forced downwardly and forwardly through the collar along an axis inclined relative to the workpiece members claimped by the fastener. One of the principal difficulties with this latter system is that the cutting blade may dig into the workpiece member as it cuts the collar.
The present invention includes, but is not limited to, the following features:
1. Lightweight, hand-held and compact.
2. Automatically actuated by the same hydraulic power supply used by the automatic tools designed for installing such fasteners.
3. Cuts the collar clearly in one operation.
4. Spreads the collar substantially out of engagement with the lockgrooves to permit stripping of the pin from the collar.
5. Generally eliminate the need to perform any operations on the pin or collar subsequent to the cutting operation prior to disengaging the two fastener members.
6. Allows disassembly of pin and collar without destroying in any way the fastener hole in the members joined together by the fastener.
7. Removes lockbolts which have been incorrectly installed, e.g. where the pintail does not break away.
It is a general object of the present invention to provide an improved device for disassembling swage type fasteners.
It is another object of the present invention to provide an improved collar cutter including one or more of the features noted above and those as shown and described.
Additional advantages and features of the present invention will become apparent from the subsequent description and the appended claims taken in conjunction with the accompanying drawings.